package g34930.td6Bis.Sources;

import java.util.Scanner ; 

public class SuiteF { 
    public static void main ( String[] args ) { 

	Scanner clavier = new Scanner ( System.in ) ; 

	int nb1, nb2, i, N ;

	nb1 = -1 ;
	nb2 = 1 ;
	i = 1 ;

	N = clavier.nextInt();

	while ( i <= N ) {

	    nb1 = nb1 + 2;
	    System.out.print(nb1 + ", ");
	    i ++;

	    if ( i <= N ) {

		nb2 = nb2 + 1 ;
		System.out.print(nb2 + ", ");
		i ++;

	    }


	}
	System.out.println("");






    }


}
